Maternal blood group in otitis media with effusion

Abstract

Risk factors for otitis media with effusion (OME) have proved difficult to apply in selecting persistent cases, or those otherwise requiring intervention. Explanations may include low predictive values of individual factors and the costs of data collection. In this study, profiles on 225 children from conception to age 7 years were compiled from medical and Health Authority records and structured interviews with parents. On the grounds that nearly all cases receiving medical intervention after waiting and onward referral are more than transitory (although many persistent cases will not receive such attention) this was taken as the dependent variable--a marker of persistence. Established risk factors and maternal blood group A were considered singly to predict intervention, then in combination using logistic regression. Maternal blood group A gave a relative risk (RR) for intervention of 2.82. The noted occurrence of an attack of acute otitis media (AOM) before the first birthday gave a RR of 6.13. When these two factors were used together, the RR climbed steeply to 26.77. These findings suggest that further research is justified into the nature of the influence of blood group A on OME, and the use of combinations of risk factors to give enhanced prediction.